Carbon for electric lights.



No. 649,55l. Patented May I5, I900.

J. F. SANDERS. CARBDN FOB ELECTRIC LIGHTS. (Application filed Oct. 1.4,1897. Rnewed Sept. 16, 1899.)

(No Model.)

4 W569 0x. M gnon/amend PIN. Ca/021m.

re. Pfias. Calf/um 0r Mg/msium Y Cal-6011.

@7 6??? %72 I Qyanird;

49 5 n n H Unrrnn STATES PATENT OFFICE.

JOHN F. SANDERS, OF PORTLAND, OREGON, ASSIGNOR TO HARRY BROWN, OFCHICAGO, ILLINOIS.

CARBON FoR ELECTRIC LIGHTS.

SPECIFICATION forming part of Letters Patent No. 649,551, dated May 15,1900.

Application filed October 14, 1897. Renewed September 15, 1899. SerialNo. 780,642. (No specimens.)

To all whom it may concern:

Be itknown that I, JOHN F. SANDERS, a citizen of the United States,residing at Portland, Oregon, have invented certain new and usefulImprovements in Oarbons for Electric Lights, of which the following is aspecification.

The object of my invention is to make carbons for electric lights whichwill give a steady, lasting, economical, and agreeable light with lesselectromotive power than is required in the existing systems of electriclighting and which will burn in end-to-end contact either with eachother or with other carbons; and my invention consists in the features,details of construction, and methods of operation hereinafter describedand claimed. In the drawings, Figure 1 is a side elevation of myimproved carbons with portions broken away at one side, and Fig. 2 aplan view ofa transverse section taken in line 2 of Fig. 1.

For the purpose of giving an intelligible and complete understanding ofmy invention I have concluded to describe,in the first place, the methodof constructing or forming the carbons, and, in the next place, theprocess and methods of their use.

In making my improved carbons I take coke, lampblack, or similarmaterial, although I may'say that I prefer to use lampblack made for thepurpose. Where coke is used it should be as free as possible from thepresence of silicates of lime, soda, or other substances, and wherelampblack is used it should be as near as possible a perfect monoxid ofcarbon and well calcined before it is used. I mix with the pulverizedcoke, lampblack, or other material a salt of magnesium, preferablycalcium oxid of magnesium, enough to "constitute about one per cent. ofthe mass when completed. I also mix in a salt of calcium, preferablyphosphate of calcium, about one per cent. The mass would thus constituteabout ninety-eight per cent. of carbon, about one per cent. of the saltof magnesium, and about one per cent. of the salt of calcium. I then mixin some binding material, such as pitch, sugar, molasses, or othersticky material. The mass is then thoroughly mixed and subjected to agentle heat to cause the parts to be thoroughly incorporated with eachother.

The mass on cooling constitutes a hard and brittle substance, so that itcan be pulverized again. \Vhen so pulverized to a very fine powder, itis poured into hot molds, where it is subjected to a high degree ofpressure and so shaped into sticks adapted for use as electric-lightcarbons. These sticks may be round, as illustrated in the drawings, orthey may be in angular form, as square, hexagon, octagon, or othershape. While the mass is in the hot molds and under pressure the bindingmaterial becomes again soft and sticky, so as to cause the particles toadhere and remain in the shape and form into which they are pressed.After the carbons have become cool I take them and pack them into acrucible, where they are held in a vertical position by filling theinterstices and the spaces between them and the crucible with pulverizedcoke, graphite, or similar material. The crucible is then covered with alid, so as to exclude the air, and placed in a furnace and subjected toa gradually-increasing heat to expel any gases formed in the crucible.When this point has been reached,the furnace is permitted to cool off,and when sufficiently cool the crucible is removed and the carbons takenout.

I have found from experience that carbons thus prepared may be burned inend-to-end contact either on a direct or an alternating current. With analternating current I have found that they give more light than onadirect current and without any noise or humming, as is the case withother carbons on an alternating current. I have found also that lampsprovided with carbons made as above do not require the usual mechanismto regulate the arc and that they may therefore be made simpler,cheaper, and more durable than the lamps now in use. I have found,moreover, that carbons made as above explained require only aboutone-half of the electromotive force that is now required in arc-lightsto produce a given amount of illu' mination. I have also found that incomparison with incandescent lights my carbons will give about twentytimes more illumination with a given current. Moreover, I have foundthat the light produced by my carbons is absolutely steady so far as theeye can de termine and more agreeable to the eye than any otherartificial light employed at the present time.

The carbons as above made are especially applicable for use with theexisting alternating electric currents. To make them equally applicableto the existing direct electric currents, so as to give them a widerrange of use and utility, I provide the carbons with a core runninglongitudinally through the axial centers of the carbons. This core ismade in such a manner and of such material that it will have a greaterresistance than the surrounding body of the carbons. V This resistancein,

the'core may be produced by adding a nonconductor of the electric'current-such, for example, as phosphate of magnesium, or calcium, orother suitable salts-to the lampblack or coke or material of which thecore is made in such quantity as to produce the desired resistance. Thecore is preferably made in the same manner as I describe in reference tothe carbons themselves. There a core is intended to be used in thecarbons, one half of the carbon may be molded first, with a groove orchannel running longitudinally through it, into which the core may bethen placed, and the other half of the carbon is then molded in the samemold and pressed onto the first half, so that the two halves, with thecore running through the longitudinal center, will'emerge from the moldin the form of a single solid carbon. After the carbons have thus beenformed with the cores in them they are subjected to the same method oftreatment as to placing them in crucibles and heating them as abovedescribed.

' To describe the composition and characteristics of the carbonillustrated in the drawings, I may say that A represents the core of thecarbon, B the body of the carbon, and O the coating of the carbon,formed of an illuminating metal, such as magnesium, calcium, bismuth,antimony, zinc, aluminium, nickel, &c.,-or an alloy of these metals orsome of them. The coating is applied to the carbons by dipping themafter they have been baked and while they are still warm into a benzinor other solution of magnesium, cal cium, or other desired metalliccarbonyl for ashort time. In this manner the metal or alloy is separatedfrom the solution and is deposited upon the outside of the carbons in asolid adhesive coating of any desired thickness; or, if preferred, thecarbons may be exposed to the vapors or gases of such metallic carbonylsheated to, say, over 350 Fahrenheit, when the same deposition of metalstakes place. It will be understood that the coating in whichever wayapplied is a good conductor of the electric current, besides being of anilluminating nature. In fact, by these coatings of magnesium or calciummetals or alloy of the same I produce a magnesium, calcium, ormagnesio-calcium light in the electric light, but in a simpler, moreefiicient, and less expensive way than is done at the present time byburning the same metals in a hydrooxygen flame. The completed carbonswill thus be formed of a core of material of poor conductivity, and thebody.

of the carbons will be formed of a material of a greater conductivity,and the coating of the carbons will be formed of an illuminating metalof high conductivity.

In operation the carbons are arranged in place in an electric circuit,with the points of the cores preferably exposed in contact with eachother, as shown in Fig. 1. of electricity must necessarily pass throughthe resistance-cores and cause them to become incandescent. As soon asincandesc'ence is produced in the points of the cores there takes placecertain chemical actions in the points of the cores. One of theseactions is that the phosphate of lime or magnesium is decomposed andphosphoric acid is set free in the form of a gas, which first occupiesthe space between the carbon points and the shoulders of the carbons.Now this gas is a better conductor of an electric current than thecores. Hence a part of the electric current will, in proportion to therelative resistances, pass through the phosphoric acid from the body ofone carbon to the body of the other. Owing to the burning or consumingof the body portions of the carbons and of the coating more rapidly thanthe points of the cores, there is a constantly-enlarging space from thecores to the outer edges of the carbons, which, owing to the continuousdevelopment and extension of the phosphoricacid gas, causes it to bulgeout, as it were, and thus form what for convenience I term the globeD,through which the electric on rrent passes, as indicated by thearrows. The phosphoric gases, however, are not the only gases developedwhen the points of the resistance-cores become incandescent, which areconductors of electric currents. There is also dioxid-of-carbon gas aswell as other gases, together with particles of carbon, calcium,magnesium, &c., which are carried from the body of one carbon to theother and which while in motion undergo certain chemical changes,especially combustion, in this way producing a very strong light ofgreat illuminating power, which light, however, is very agreeable to theeye. Owing to the presence of the phosphoric-acid gas, the light in ameasure partakes of the nature of a phosphorescent light, which, in myopinion, adds to the agreeable nature of the light. There is thus formeda new kind of light from any electric light now in existence of which Ihave any knowledge, what may be termed a combination of the present areand incandescent and the magnesium or calcium lights. This,

as I understand it, forms a new system of electric lighting.

It will be seen that the resistance in the cores is of great importanceand that by it the length of the light-globe,as I have termed it, iscontrolled more completely than the arc is controlled in the presentlamps.

The current 1 It is clear that in this new light all the current must atfirst pass over the points of the resistance-cores and in so doing causethem to become incandescent and so produce the globe, as aboveexplained. Moreover, it is clear that whenever the globe between theunconsumed portions of the body and coating of the carbons becomes toogreat, so that its resistance is greater than the resistance of thecores, the electric current is naturally and instantly compelled toagain seek its passage through the cores proportionate to the differenceof the resistance between the cores and the globe. As the current thusreturns, as it were, to the cores the core-points are again more rapidlyconsumed and again more freely supply the gases, which act as conductorsfor the current in the globe, so that more of the current again seeksits passage through the globe than through the cores. As the body of thecarbons is formed of a material of greater conductivity than the cores,the electric current will more readily pass through such material thanthe cores, and as the coating of the carbons is of still greaterconductivity the current will more readily pass through the coating thanthrough the body of the carbons. The difference in the degrees ofconductivity in the several parts, as above explained, will cause thecores to become incandescent,while the body and coating of the carbonswill remain comparatively cool. If the points of the cores were notexposed at the commencement, the more rapid consumption of the body andcoating would soon cause them to become exposed and assume the relativeforms shown in Fig. 1. In this way, as above explained, the passage ofthe current through the globe or through the cores is madeself-regulating, so that practically the resistance afforded by thecores and the resistance afforded by the globe are kept constantlyequalized, so that the light is maintained in a regular, steady, andunvaryin g condition so far as the eye can discern. The electriccurrent, owing to the character of the different portions of thecarbons, is made to regulate itself and so to dispense with all themechanism usually employed in the arc-lamps of the present time toregulate the are, and it does so with much greater simplicity andprecision than can be secured by mechanical means. My carbons thereforerequire a very simple lamp and merely enough mechanism to hold them incorrect position with reference to each other and to permit them to feedas they are consumed.

Furthermore, very beautiful color effects may be produced'by treatingthe carbons before they have been coated to different color solutions.For instance, to produce a strong red light I dip the carbons, made asabove, after they have been baked and before they are coated with anymetal into a solution of strontium for some minutes, so as to give thissolution ample time to permeate or saturate the whole body of thecarbon. They are then explained.

taken out and dried until the moisture has been expelled. These carbonscan now be used as they are, or, if preferred, they may be coated withany of the metals, as already To produce a blue light, the carbons maybe treated, as above explained, with a solution of indium, and toproduce a green light they may be treated to a solution of lithium. Inlike manner other solutions may be employed Where other color effectsare desired. In all cases, however, whatever be the color solutionemployed the process and mode of treatment are the same as alreadyexplained in reference to the red.

In addition to the various advantages that I have enumerated above inthe description of my invention I desire to call attention to the factthat my light is particularly adapted to indoor use, owing to the factthat a large quantity of ozone is generated or produced from thecombustion of the phosphoric-acid gas as I understand it.

\Vhat I regard as new, and desire to secure by Letters Patent, is-

1. As a new article of manufacture, a carbon for'electric lights havinga core in which a phosphoric salt forms one of the ingredients, a bodycomposed of carbon material proper, and a coating composed ofilluminating metal, substantially as described.

2. As a new article of manufacture, a carbon for electric lights havinga core composed of resisting material in which a phosphoric salt formsone of the ingredients, a body composed of a material of less resistancethan the core, and a coating composed of material of less resistancethan the body of the carbon, substantially as described.

As a new article of manufacture, a carbon for electric lights having acore composed of resisting material, and a body composed of ahomogeneous mass of carbon material proper and oxid of magnesium, andphosphate of calcium, substantially as described.

4;. As a new article of manufacture, a carbon for electric lights havinga core of resistance material in which a phosphoric salt forms one ofthe ingredients, substantially as de scribed.

5. As a new article of manufacture, a car bon for electric lights havinga core of resistance material in which a salt of illuminating metalcomprises a component part, a body composed of carbon material proper inwhich a phosphoric salt forms one of the ingredients, and a coatingcomposed of illuminating metal, substantially as'described.

6. As a new article of manufacture, a carbon for electric lights havinga body composed of carbon material proper and a light-giving salt havingresistance qualities, and an adhesive coating composed of metallicmagnesium applied directly to the carbon, substantially as described.

7. As a new article of manufacture, a carbon for electric lights havinga body composed of carbon material proper and a light-giving salt havingresistance qualities, and an adi hesive coating composed of an alloy ofcalcium and magnesium applied directly to the carbon, substantially asdescribed.

. .8. As a new article of manufacture, a carbon for electric lightshaving a body composed of carbon material proper and a light-giving salthaving resistance qualities, and an adhesive metallic coating composedof an illu m inating metal applied directly to the carbon, substantiallyas described.

9. As a new article of manufacture, a carbon for electric lights havinga core composed of resisting material, a body composed of carbonmaterial proper and light-giving metallic salts saturated with a desiredcoloring salt, and acoating composed of illuminating metal,substantially as described.

10. As a new article of manufacture, a carbon for electric lights havinga body composed of a homogeneous mass of carbon material proper and aphosphorescent light-giving salt, and a core formed of a light-givingsalt having resistance qualities, whereby carbons may be burned inend-to-end contact, substantially as described.

11. As a new article of manufacture, a carbon for electric lights havinga body of carbon material properand a core composed of resistancematerial and a phosphorescent lightgiving salt, whereby carbons may beburned in end-to-end contact, substantially as described.

12. As anew article of manufacture, a carbon for electric lightshavingabody composed of a homogeneous mass of carbon material proper andlight-giving salts, a core composed of resisting material and aphosphorescent light-giving salt, and a coating composed of illuminatingmetal, whereby carbons may be burned in ,end-to-end contact,substantially as described.

13. As a new article of manufacture, a carbon for electriclightshavingabody composed of a homogeneous mass of carbon material proper andlight-giving metallic and phosphorescent light-givin g salt,and a coreformed of resistance material composed of phosphate of lime andmagnesia, whereby the light is made self-regulating, substantially asdescribed.

14. As a new article of manufacture, a carbon for electric lights havingabody composed of a homogeneous mass of carbon material proper andlight-giving metallic salts, and a core composed of resisting materialand a phosphorescent light-givin g salt,whereby the arc is madeself-regulating, substantially as described.

'15. As a new article of manufacture, a carbon for electric lightshaving a body composed of a homogeneous mass of carbon material properand light-giving metallic salts, a core composed of resisting materialand a phosphorescent light-giving salt, and a coating composed ofilluminating metal,whereby the arc is made self-regulating,substantially as described.

JOHN F. SANDERS. lrVitnesses:

THOMAS A. BANNING, ANNIE O. COURTENAY.

